Copying over plug-ins is not recommended. They are supposed to be installed.

Make sure as well that if you point (in preferences/plug-ins) to a previous plug-ins folder, that you do not do it for the root of the plug-in folder of your previous version of Photoshop. Do it for a folder that contains your third party plug-ins.

The root cause of this issue has been traced to an apparent bug in the public beta version of CS6. Its been reported to Adobe and they are looking at it. There were no issues with CS6 m.122 and this problem started with the public beta release (m.415). Noise Ninja should not be crashing Photoshop because of this problem however. It should merely report an error processing the image. PictureCode will release an update very soon. The update will fix the crash of CS6 and I expect it to have a workaround for the CS6 problem as well.